SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2737ed624c0d13239bfdde38036fb43da93ab777e5c89bc6e26a4778bb613d79' 
  AND token = 'PQPS42nLBWOGYFi8pCgS92NN7YOFEtfebIXfREBgcCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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