SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5259adffc9cd5f37bc3f9a90be545148a30b1b31f30cf08648344447644c6e0' 
  AND token = 'nm1uIWeur21pVfN2d9RR/MpAu38TTeRC+ZVlpktTS3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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