SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24240516354143fb6bcee371c232d186fa72a8766311bad0456688cb3e1eacd3' 
  AND token = '8Nd8iZBSAOF3XE8QOI2B7vJdV2OckbMZ0P2B9zS+H3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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