SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d75bd0f30a5049faae6bb0eb600c4fe79d739f1080036ef422e57ce73d972d4' 
  AND token = 'ymCfgyaSO+otpc4ucPupfBIRKkf1GtqSvSajeKdStBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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