SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a7fa514d99434966c3f87d47becf201519507dd32fa0ff566f35611c9221742' 
  AND token = 'HmZzU8yxLuvLDusu+KgeKEVYsbGPLIXgZCNPrThw8tM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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