SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8cad085e25d1b4a758c3cd8dc2b49ae26b276db2d33651f7d050fab60f7cd5f' 
  AND token = 'La18BW/i7K4kW8HGVBgGo7wRRG8hp7nhiC4ZMzZz6jc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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