SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '684e98f4ffc318ceaf18c923817c5ee13df70205c896bd16c91ff1bc30cb5187' 
  AND token = 'n5BFBMOHD0R3Kcc2JxaMAvuP4UjThEhgQ9mjg1rBpqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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