SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52b86b563d96ca78abd7a4ad654f2ed3fbfc5b5b270454a1c8f034a916d20774' 
  AND token = 'fHQ3gXm7W+nXePYcMYqFzctgxKRfkW2J9JXOSMzLv9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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