SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79abf865df2427186d67a984345cd06122b6e0f891589d7d1273e2263dcb1567' 
  AND token = 'AL23nFLBEW3jKZuZgMw6aTWrQenCa85SH4CqtB95xpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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