SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '008a691c3e2373537db458c0ab5306ed8527fcd5956ebf80d34e55ce6dcd6846' 
  AND token = 'UA0e5O0SeAosbuwptzWDGPqiypo3Wvw2Jnr8/EkasJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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