SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb443e198a014702e8438d36668b11228d5f4354519b4d4a2f9f468d96c748e0' 
  AND token = 'Deshg2nXC4uW5vTANVnja7jd1MLJdCiRwZewsU7BKuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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