SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cd1af5ba1cea905f1a18fbbe529070f0d6a62f3fd4eba3eff421cd3a2234451' 
  AND token = 'jpbpUp0LO/yL4HzAyu0HQkrkkFPlqUnALAm5uKDcqZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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