SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aadc456d4fb2186f27fb3d7a03a6413f40bdd556fcf6ff2b51f7633978546569' 
  AND token = 'nBotw0HqL7LYCygYgGZtuOgwelyAmpmdn6bCzlrpFvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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