SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a27126d26bd54cd4d8e42b8f1b91746f0e8b54a0ce03a28c44a51b1a0dab9165' 
  AND token = 'VG0rfy7gExfmH/LuANFrbPefwJ18KlxbKJig5Juvwsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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