SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcc686f7a48d77d8b09482c0dd9452941ec18e85bdb36736ea691591d7df4f6d' 
  AND token = 'juMAdzFvXusLeLAxD8QhqPDprwVlraZIrGJkFVOtF+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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