SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56c170c943e518b34c3f0ffdddb57b6405b73e6d157fbfd69a85d52db66d4352' 
  AND token = 'd5gpLC8Vo6+gMxpZ+T31inOY1kqrU7ucXSGkGkIqwsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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