SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56a5162c49d49a486d8a256da5eaf13647d9c1af01946056c8e8b6f28dbe9203' 
  AND token = 'DhCS0xHiadIgjGxRizZDnQsih/GGZplLbMYCJzB/dLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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