SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '275762366d7938c3adbb05c15e32849a8043de3bf4f21b750b9051a310711136' 
  AND token = 'lRKtKWTNlkeBcgQIHPvNLwibhn2ZjsS2aAOOJFWrxPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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