SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4990310fbac147e39505c237d140fe99cf67f46acf157f6eb657251c5c09041d' 
  AND token = 'xsYkhByuYZ6Y/I8aeBWjtSqIM9z/FM+mVnUx6YUcXu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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