SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '332ef2af0ab5525ccbafa57470ed351302a369519bedcfa7b5515173c64a3ada' 
  AND token = '8dcwM6irPExvUWEnM0R60bA7YZZ3HbXdxACHZup+2s0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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