SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'affca51e6e61f80e76a9b957c823b1af6bc6fc256e3bc47a6e0c79f059339fb4' 
  AND token = '9giDyGrPDHK3IZ0OFwe+oB6qecmQgWS4g8n+kqqCQIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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