SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71b176df965997aa5d66eed0e0a69028d45f108817806b1e69a6dd7dae53ebaa' 
  AND token = 'tjEVY5Lb06xflDEctG8dv7/BE1LNWehSpuZena7JsiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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