SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77f3cd0e6b521b242f75e5f6efbb7077580857887a98e565a895ac1092f42011' 
  AND token = 'HhJTAxbtLYNRnJTJ5iWFpcUc3FO9YJScRxSh8pBwkH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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