SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70d2ca2b6c8c75209ef5f19b78bba7234d3075ccb791ff4d298b6dcf100a16f2' 
  AND token = 'wygFToUmE1HuWDgWWPi6UEDWnbOXKBIXZB0x4z2jEpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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