SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9855667cf88e25a47565c35480ee750b268015f9e767a8c61f61dd4d92507a52' 
  AND token = 'aP1AzHvEGzyGJKzfBnQUFpagBCM1OGh1Qcv28OJawqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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