SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fd78199cbe51cd99a5b284e4c79f866611766ee4a46a438fe4aef2d5022be87' 
  AND token = 'NLmu7S757pJcUrzNnr0IgMta1jmN7n85HhUvIBsPoNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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