SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cad787a9eb906eddab324e7f0204811f5e7c086681d565693be23f308fc85de' 
  AND token = 'hWvZE2BJCjK+oTjvs4V75c/lP9ghjUlGOC09UdJgnVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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