SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa683f332559ece08cbad7b11f99e2af9e503b36e36d8962fa903ece2b0a5708' 
  AND token = 'nls0zeYsgmSRwfrCS9LqGGPpdx2JNwxfFUpcBhE/y3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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