SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03e993750cff4856227d8bbb388b0fecb914d8b1772a1e1f507a6c341c4af251' 
  AND token = 'YzWaUX852A/LXyQ/tE0EVE3KJK+e/3G30EqYayy2GHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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