SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93a76821628e61c49e16023c15c4330c99dcca9b61d530a60a460e52bc1cc0bd' 
  AND token = 'ROMeBz19Ssy5xEPUefP4m60DB826/NTbj04sykS64kI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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