SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0afe462d8a859e03bdf730c663fed80b0e36dde89f154d7555feea4132fd392' 
  AND token = 'C8hVqD73CymkdpLnLBhGRHjh+fhyNkPlgZqyqTl78ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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