SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '150472231b57f70b05a693702ecb84da15d6931fbb02a0b61235b048002ee8b2' 
  AND token = 'duiVJVZolkegJKwhxsm7+ei3sYrDjQqQiAMzQJRgWlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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