SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c491737bbd720aa441437a01c827e6df0ffabdbbe4308290e0b9f4479e0437ce' 
  AND token = 'VzYzzR52PWJURh2WsvF6kgAr2784ESJvi4JbcMgbr7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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