SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30a5fa73b187cfc868658a67d1d42e18a30f2869bdf91f2c742df686557ba3d9' 
  AND token = '+VKuGDrLpFAKiZkOzmpyr24loM467tBeNyTXCDHOvRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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