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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0a64a251fa4022293639e11756a8c6ea3fb02a8a235f35d6b0e8776027ba849' 
  AND token = 'eCHZlXMQtw8tGoN32VlBlVAt1n+F1fvCntwRcsQghkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}