SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87cfc0cd0de16fb63b5357138924345472ef7c59fa8e3d0008881c461d35c131' 
  AND token = 'fuWHaK/IkCLd8Fg+PNFG4xZpc61bePJbqFBkPhwzx2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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