SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '677378f39de52b65607939994bfb17010949ca5f4a33710181e4aae5e0369eb5' 
  AND token = 'L6kFdpSijKiHfrsnxKx/3a94srXdmtSbVAanvrNTn8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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