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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6940d429ebba7a4ad4fb8ba33b10abf58ec49129571b200c8ebb9f9cc748b94' 
  AND token = '7IjlZSK68ZFJvrc9y+0OuNtVs6nY34dtUqAYrRo3hRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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