SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b25b1cf131c12c7d413313c5238d9d6d98e1a0ae2b3813abcea546adc05359b' 
  AND token = 'gCFiRW2NS/e3T18BeIflUShATCFDt9a8OMhnoyxAUM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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