SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d4e04c9c6a7399c50f44f281aef335da8ed00887261773826f0aeb2813b661e' 
  AND token = 'JpbBtWwmRfXODJwi7W2+iB3owsqjjPy+A5ZraoY/+UM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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