SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5a08ea82c421c50da699cdb7989ee393668778d0cda4a98274f231400b466d5' 
  AND token = 'SxrCC/IUbOJvfI1e+/XbQtKzlQVoegMN/27sfce1bf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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