SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '931ef8de4838144ab28f71984a5ce7cf2572388b99f7ad13638b7fae955cfffd' 
  AND token = 'm244A1X7Z/j3q+wkIFhX5KWrPpUyqM81oBOVrJWUm+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}