SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96c75a7fd19db8a6eea9670898537726d12cb54512004993abebba578d00559e' 
  AND token = 'kwHdJG5UBV7hKJE6DDXS/OHeJ+E39ZDG92ISSixR5lI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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