SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '340997b61be1883727d9fbb0b907b2bff9df89fc61afb1f9efb577cf746b6e7b' 
  AND token = 'Pb98KiOlKzy4FPiCJwZk744qxgJJqOyuatuUF1fnWoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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