SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf362993863a09c864ebfe578a1b2fb30e6111ac7667c9072c3185da7d5fd3c8' 
  AND token = 'fZyTZ2YjiCI6abjWtgLJo+0gi7HjW11wyaEoB7V0rQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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