SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '720a01614a151427cff35fbac1427b55a54c5d943f43335baa95581f98534073' 
  AND token = 'rEw2+r6dUgj1pyZgGHjxDL1Ce3L1TaGnW5gf2Rc5mrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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