SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd93aae6f1d9e4f3a745e7a176360119c84a60b877cea4f27a9465858a1e2f690' 
  AND token = 'yvq8p9HMuAgLKfnyXNZTsUYcPBvaZ7hkKUz/5n2DcGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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