SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f52364f1fd7a85fd6d208fdebdd215ac8161abeec078513252686cea07922e4' 
  AND token = 'KkaTMqb99xaW8zHLTC5f8a/w6MSwaYJW2jkLhtNUHPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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