SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12c807e3d7494adf27493400530a348344a94235849548c4c73dc96e3cea58d8' 
  AND token = 'gVpq9rUjRZeYdIcbVwUqhMzZXTz94m7zrG5FjYkGTxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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