SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5efe7723902299c6cb5a1d7655e8717d7c14add45d5be609bc4c5488a2296c78' 
  AND token = '5rAqpCGLn74CJPdFVz8I8/njZMp+PThOCyiqDPIGidQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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