SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e5930bd87c33ef10ec5b516c7eeee8140ca9d876b2f273717a64a38de204970' 
  AND token = 'rZDs08dMjZYbtuOIQoVyJm59ECZyYMPjukM9VCA/vEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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