SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cb644233cbeecfc9e9bec2da4cef0d06f442a1c911f07b9341b70cb4771817d' 
  AND token = 'iBvOkST+sZXJbA97DuhRdqqg1+5UBSDAw9GhVDKoIjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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