SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '744554937b7f68b3fc36bb20d06b07da133e74d2e6e445afabbc59c82dc0aab0' 
  AND token = 'iP74dubFeFtuDhk80L1vmUzxhnwmCcFD4sSSaYv9XOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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