SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '110fc5e6fe232c120056188a1ba9dba929ac1a5556a9f7f3421955d3234a4a77' 
  AND token = 'XBTdmQGvrsR0JGkzBUJQGTvXJjnCFqW23lybZZqtwiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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