SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e801715eb25226906566c5cae59de33ea034d5506e6569e573f191ae5e71626' 
  AND token = 'aUWfVWw8n2dimlGGi+56TyPbPmB7OHiNTNymmFmW5wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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