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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d1fd4502dd8c6812ee2d84644033c7e6f20438ba7be226107a51f890fed86c9' 
  AND token = 'i6xkOj+kd3FZrUSfZEqTeoG1mN3X+bHJoE7xWhMf7Mw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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