SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bf75996e0567515522b9779dd9f2eb9e03b76cf4b182813de4089e05f837fcb' 
  AND token = '7fBSLN+zZTf/5j+o4bJXPMgzAK/0FOnKp9Wxs8MGGqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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