SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b696d98e8775ea015239bb0b0e5f3b864e08624e375a87689db8670d68277ecb' 
  AND token = 'wrY2XLoFK4XLvouZguZIDq9N8uFce10jWfCjgHZgd1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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