SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '038746ce0abf6cca32d6b6cec2df5285e2a61bdcb2a2780d94757bafb8269664' 
  AND token = 'Mu7kftjiOCViOAspzIpcd804oGRkeu+dkhopg8pBMBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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