SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fb2e259cfe25bf58cee4f631e0c7f6bd08133be229515fffd25c00ad2ff69d7' 
  AND token = 'ln3QthGJSl/OJd2RAbiiK2wY83okOZDJnNlotCTuMas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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