SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1f8ec7527db91d43570a6b6c47d766222bf1fb9ee5eb134b94a49973ace8287' 
  AND token = 'RvqcV9jw2BDyq6Yn7fabSw7zleIq/EYZpogGTCLjfs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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