SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70f4cc902a89320162e5e808f25b2ec178a3d376fc06f2dd22f5d220fd9fc9c7' 
  AND token = '2CIZWXhSmMRIbaKF3bJT8gPi7JkJtvqShyEznDqEg/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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