SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '053b565557c67d47ac78c23ee1feb646c2fdbd497325f6be33b9632099586f0b' 
  AND token = 'RrKDet017leDTe3T693TgMxVrfaCufThzCkqGfdZ/3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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