SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '394c03c763e8cb4971d75d52bdb4181978b14d200bdf96de728edcaa618f3648' 
  AND token = 'lTp1oSTVCqcGjeN+Y3xXL50hjG2lH+1/YQjJSK2KLeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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