SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6ff9343d789c9ae0346f4fe7de20fb7fc1b338c49147b2fe4b25c19d5dd5c7f' 
  AND token = 'ZOaN46587brHBwtLUMrvXnAIkMhMcPdulwQpSjsoyc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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