SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7982e8d6d9dce13488aeb4dbc1203eadd08b325c215df58735cacb20f497556f' 
  AND token = 'yxHiljG1KDlMK6wi92YioXiSWa+WGmiaed7Socw6CG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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