SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c64937e36cc87b9ecbfa0840188abb9854b261735ced9769f5f41646b656f97a' 
  AND token = 'DZUG4qHiTW7nWecsSuMHaMlN2L1cbV850JbpcbHC37s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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