SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11c64763c7d6cf6878bc4d1a14ed8a82fa72d091576555df8895005a77fe111b' 
  AND token = 'WcKsjGnlBzViYChAmiDMyrflNNw46wVRnycUp62bkWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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