SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66d1c81fe99217c5660a3b38fc38bc025b53c18670bf4276540590aadec085f7' 
  AND token = 't5GtLYWh3ECzV9LpnkBBcXnDdcrcW77yw+Urj1vvZwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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