SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afb3e5c065236ac743d3d51c0f753f579232889cd478d6b578bed75a783739aa' 
  AND token = '3MZvBJn86OO8Tl09hV3sJfxtBCV97BYHGdtn2Jw/+ig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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