SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '05d78b4190d588a5c88e58e71bba8c2da2b11772cdd8d28fa2a851530df49b77' 
  AND token = 'X923nbP29dbyIavucXPXGGqXSpnjA5YmapGpunryhmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}