SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b48d72e6f1f386e7faaeb7b8739e9b7bfa8609f2908069e9b278ca8ba992cd50' 
  AND token = '8k1qt4Eo47zVaxAsqNKf2vH/hH+986lH4FXQJmU35Rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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