SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c56399ece601a966453f9a26bbf9224066c20693ded75cb6369347bb97c761a' 
  AND token = 'B5DmQycKkF5ozI+tgMSuTvHfeiGB4wEwrCG43p9Ipk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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