SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28236d509886a2b2cc5f058055f598fa45a93bce1a280e19ebe8e07858ba84a8' 
  AND token = 'JkEAvjkZ6ekmONbSTTrsrjJFZjF2htnwp20VFQG582w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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