SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6e018791803da443d203f9bda7c1a6508e4550bbe2059dd65d102bb7b194248' 
  AND token = 'eSjTqJwIxEFl921oBps4RqmzEOMbsS7tMEITqiEvKxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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