SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a372b0f8cd146538a6284a0ed0c93184dbbadaafea2d4f467b5eca0c238c8c99' 
  AND token = 'FzrwQ4qSPovb0gJCVsHQsPU4gRK8fNrTaYe73VENJ+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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